Known devices for printing on packages include those that apply a colored or multi-colored print to the package. Such printing devices typically include a transport path on which printing takes place using printing units or print heads along the transport path that produce the color sets. Typical print heads are those that can be actuated electrically or electronically, such as inkjet or tonejet print heads. In the latter case, the print head applies directly to the container wall via direct printing, thus producing the printed image.
It is also known to include drying and curing devices. These are used to dry or cure a freshly printed container. However, in the known printing devices, the degree of dryness, and thus the degree of curing of the printing ink, cannot be determined directly within the process.
One disadvantage of this is that unless the printing ink that has been fully cured, the printed image applied to the container wall may smudge after awhile due to contact with other containers or parts of the machine. This leads to a printed image quality that is impaired overall
Another disadvantage arises because the drying and/or curing of the printing ink greatly influences its ability to migrate through the container wall into the container interior. Thus, improper drying or curing also creates the risk of printing ink, or constituents thereof, migrating into the product contained within the container.